Android grpc with UDS is slow to connect sometimes #11442
Description
Hello!
We are using gRPC with Unix Domain Socket (UDS) on android. We are using waitForReady() and are bring our gRPC server up when app is active. However, sometimes when opening the app the connection is slow. It seems like some back off is applied unnecessarily. When enabling logging we've come to see the messages below. Connecting can take anywhere from a few 100 ms to 30+ seconds, but usually 0-3 seconds.
We've tried using the channel.resetConnectBackoff() before trying to connect again, and also channel.enterIdle() before exiting the app w/o any improvement.
What version of gRPC-Java are you using?
Latest (1.65.1)
What is your environment?
Android
What did you expect to see?
Connecting and then Ready state.
What did you see instead?
Connecting, sometimes TransientFailure and then Ready.
We also see the following message, sometimes multiple times (=reconnecting with backoff?).
[Channel<1>: (dns:///localhost)] Failed to resolve name. status=Status{code=UNAVAILABLE, description=Unable to resolve host localhost, cause=java.lang.RuntimeException: java.net.UnknownHostException: Unable to resolve host "localhost": No address associated with hostname
at io.grpc.internal.DnsNameResolver.resolveAddresses(DnsNameResolver.java:223)
at io.grpc.internal.DnsNameResolver.doResolve(DnsNameResolver.java:282)
at io.grpc.internal.DnsNameResolver$Resolve.run(DnsNameResolver.java:318)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:644)
at java.lang.Thread.run(Thread.java:1012)
Caused by: java.net.UnknownHostException: Unable to resolve host "localhost": No address associated with hostname
at java.net.Inet6AddressImpl.lookupHostByName(Inet6AddressImpl.java:156)
at java.net.Inet6AddressImpl.lookupAllHostAddr(Inet6AddressImpl.java:103)
at java.net.InetAddress.getAllByName(InetAddress.java:1152)
at io.grpc.internal.DnsNameResolver$JdkAddressResolver.resolveAddress(DnsNameResolver.java:632)
at io.grpc.internal.DnsNameResolver.resolveAddresses(DnsNameResolver.java:219)
at io.grpc.internal.DnsNameResolver.doResolve(DnsNameResolver.java:282)
at io.grpc.internal.DnsNameResolver$Resolve.run(DnsNameResolver.java:318)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:644)
at java.lang.Thread.run(Thread.java:1012)
Caused by: android.system.GaiException: android_getaddrinfo failed: EAI_NODATA (No address associated with hostname)
at libcore.io.Linux.android_getaddrinfo(Native Method)
at libcore.io.ForwardingOs.android_getaddrinfo(ForwardingOs.java:133)
at libcore.io.BlockGuardOs.android_getaddrinfo(BlockGuardOs.java:222)
at libcore.io.ForwardingOs.android_getaddrinfo(ForwardingOs.java:133)
at java.net.Inet6AddressImpl.lookupHostByName(Inet6AddressImpl.java:135)
at java.net.Inet6AddressImpl.lookupAllHostAddr(Inet6AddressImpl.java:103)
at java.net.InetAddress.getAllByName(InetAddress.java:1152)
at io.grpc.internal.DnsNameResolver$JdkAddressResolver.resolveAddress(DnsNameResolver.java:632)
at io.grpc.internal.DnsNameResolver.resolveAddresses(DnsNameResolver.java:219)
at io.grpc.internal.DnsNameResolver.doResolve(DnsNameResolver.java:282)
at io.grpc.internal.DnsNameResolver$Resolve.run(DnsNameResolver.java:318)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:644)
at java.lang.Thread.run(Thread.java:1012)
}
Steps to reproduce the bug
Setup gRPC with Android using Unix Domain Socket and then open/close app.